Segmental arterial mediolysis: report of 2 cases and review of the literature

Acute abdominal pain: a challenging diagnosis

We hereby describe a case of an acutely ill 41-year-old male without any medical history who presented with an acute abdomen in the emergency department. An abdominal CT showed a dissection of the coeliac trunk and infarction of the spleen. Because of a presumed diagnosis of vasculitis he was started on high dose IV steroids. However, after additional testing the diagnosis of segmental arteriolar Mediolysis (SAM) was made. In this case report we describe the presentation, diagnosis, treatment and follow-up of this patient and provide the readers with background about common differential diagnosis and criteria for diagnosing SAM.

How I treat unexplained arterial thrombosis

Most arterial thrombotic events have a clear atherosclerotic or cardioembolic etiology, but hematologists are frequently asked to assist in the diagnosis and management of a patient with a nonatherosclerotic and noncardioembolic arterial event, referred to here as an unexplained arterial thrombosis. Because there is an assorted list of factors that can precipitate an arterial event, we present a systematic diagnostic approach to ensure consideration of not only primary hypercoagulable disorders, but also pro-thrombotic medications or substances, vascular and anatomic abnormalities, and undiagnosed systemic disorders, such as malignancy and autoimmune diseases. We also review existing literature of the role of hypercoagulable disorders in arterial thrombosis and discuss our approach to thrombophilia workup in patients after an unexplained arterial event. We conclude with 3 representative cases to both illustrate the application of the outlined diagnostic schema and discuss common management considerations, specifically the selection of anticoagulation vs antiplatelet therapy for secondary prevention.

Natural history and management outcomes of segmental arterial mediolysis

BACKGROUND

Segmental arterial mediolysis (SAM) is a poorly understood, nonatherosclerotic, noninflammatory disease resulting from arterial medial degeneration. Patients may present with aneurysm, dissection, stenosis, or bleeding from visceral or renal arteries. Treatment algorithms are poorly characterized.

METHODS

A retrospective review of all patients diagnosed with SAM was performed at our institution. Patients were identified by established criteria that include clinical presentation in combination with radiographic and serologic findings. Demographics, presenting symptoms, diagnostic evaluation, management, and outcomes were reviewed.

RESULTS

There were 117 patients diagnosed with SAM between 2000 and 2016; 67.5% (n = 79) were male. Mean age was 52.7 years (range, 23.4-90 years); 69.2% (n = 81) presented with acute abdominal pain, 22.2% (n = 26) with flank pain, and 19.7% (n = 23) with back pain; 15.4% (n = 18) had abdominal pain longer than 30 days; 13.7% (n = 16) had acute hypertension, and 5.1% (n = 6) were hypotensive; 10.3% (n = 12) were asymptomatic. There were 93 (79.5%) dissections and 61 (52.1%) aneurysms. Hemorrhage was seen in 10 (8.5%). The celiac axis was affected in 54.7% (n = 64), renal arteries in 49.6% (n = 5 8), superior mesenteric artery in 43.6% (n = 51), and inferior mesenteric artery in 2.6% (n = 3). After diagnosis of SAM, aspirin was prescribed in 60.7% (n = 71). Statins were prescribed in 29.9% (n = 35). Antihypertensive medications were prescribed in 65% (n = 76), including beta blockers in 42.7% (n = 50); 40.2% (n = 47) of patients were prescribed anticoagulation. Interventions were performed in 26 (22%) patients; 13 had endovascular intervention only, 9 open surgery only, and 4 open and endovascular interventions. Of the 17 patients undergoing endovascular intervention, 19 procedures were performed, most commonly embolization (78.9% [n = 15]), followed by stenting (10.5% [n = 2]). Of the 13 patients undergoing open surgery, 14 procedures were performed, including arterial bypass (50% [n = 7]) and splenectomy with aneurysm ligation (15.4% [n = 2]). Other surgery involved thrombectomy (21.4% [n = 3]) and angioplasty (14.3% [n = 2]). Only 11.5% (n = 3) experienced a perioperative complication, including one hematoma, one abscess, and one death secondary to ongoing hemorrhage. Follow-up imaging was performed in 96.6% (n = 112). Mean follow-up was 1258 days (range, 2-5017 days). Of these, 27.7% (n = 31) had regression, 43.8% (n = 49) stability, and 28.6% (n = 32) progression. Average time between initial diagnosis and progression was 666 days.

CONCLUSIONS

SAM is an uncommon disease that may require intervention; it is therefore important that the vascular surgery community be aware of this disease. Follow-up imaging is required to monitor for disease progression.

Segmental arterial mediolysis (SAM): Systematic review and analysis of 143 cases

Segmental arterial mediolysis (SAM) is a rare but serious nonatherosclerotic, noninflammatory vasculopathy of unknown etiology that often results in dissection, aneurysm, occlusion, or stenosis of, primarily, the abdominal arteries. Current literature lacks consensus on diagnostic criteria and management options for SAM. This review summarizes 143 cases and aims to advance appropriate recognition and management of SAM. Literature review of all relevant SAM case studies from 2005 to 2018 yielded 126 individual SAM cases from 66 reports. We identified 17 additional SAM cases from our center, bringing our analysis to 143 patients. Patients with SAM were most commonly men (68%) in their 60s. Hypertension (43%), tobacco use (12%), and hyperlipidemia (12%) were common comorbidities. Abdominal pain (80%) and intraabdominal bleeding (50%) were the most common presenting symptoms. Computed tomography was the most frequently used imaging method (78%), and histology was available in 44% of cases. The most commonly affected vessels were the superior mesenteric (53%), hepatic (45%), celiac (36%), renal (26%), and splenic (25%) arteries with aneurysm (76%), dissection (61%), and arterial rupture (46%). Treatments included coil embolization (28%), abdominal organ surgery (24%), open arterial repair (21%), and medical management (20%). Case-specific treatment modalities yielded symptom relief in the vast majority (91%) of patients, with a mortality rate of 7%.

Rare Mesenteric Arterial Diseases: Fibromuscular Dysplasia and Segmental Arterial Mediolysis and Literature Review

Fibromuscular dysplasia (FMD) and segmental arterial mediolysis (SAM) are noninflammatory, nonatherosclerotic arterial diseases that cause aneurysm, occlusion, and thromboses. These diseases are rarely seen in mesenteric arterial lesions; however, as they can be lethal if appropriate management is not provided, the accumulation of clinical information from cases is essential. We herein report the cases of a 57-year-old man diagnosed with FMD and a 63-year-old man diagnosed with SAM. We conclude that an early diagnosis with imaging modalities and clinical information followed by the appropriate treatment improves the prognosis of these arterial diseases.

Diagnosis and management of fibromuscular dysplasia and segmental arterial mediolysis in gastroenterology field: A mini-review

The vascular diseases including aneurysm, occlusion, and thromboses in the mesenteric lesions could cause severe symptoms and appropriate diagnosis and treatment are essential for managing patients. With the development and improvement of imaging modalities, diagnostic frequency of these vascular diseases in abdominal lesions is increasing even with the small changes in the vasculatures. Among various vascular diseases, fibromuscular dysplasia (FMD) and segmental arterial mediolysis (SAM) are noninflammatory, nonatherosclerotic arterial diseases which need to be diagnosed urgently because these diseases could affect various organs and be lethal if the appropriate management is not provided. However, because FMD and SAM are rare, the cause, prevalence, clinical characteristics including the symptoms, findings in the imaging studies, pathological findings, management, and prognoses have not been systematically summarized. Therefore, there have been neither standard diagnostic criteria nor therapeutic methodologies established, to date. To systematically summarize the information and to compare these disease entities, we have summarized the characteristics of FMD and SAM in the gastroenterological regions by reviewing the cases reported thus far. The information summarized will be helpful for physicians treating these patients in an emergency care unit and for the differential diagnosis of other diseases showing severe abdominal pain.

Segmental arterial mediolysis presenting as spontaneous bilateral renal artery dissection

The commonest site of primary dissection involving the visceral vessels is renal arteries; however, spontaneous bilateral renal artery dissection is an extremely rare entity. Spontaneous renal artery dissection (SRAD) is rarely a cause of renovascular hypertension. Segmental arterial mediolysis is a rare arteriopathy of unknown etiology which is a nonatherosclerotic and noninflammatory condition. We report a case of a 51-year-old male patient with spontaneous dissection of bilateral renal arteries with clinical, laboratory, and angiographic findings consistent with segmental artery mediolysis. Early diagnosis and treatment of this condition will decrease morbidity and mortality.

Case of Segmental Arterial Mediolysis

Segmental arterial mediolysis (SAM) is a rare, non-inflammatory, vascular condition that predominantly affects medium-sized to large-sized abdominal arteries and can present with haemorrhage into the abdominal cavity. We report the case of a patient with SAM of the coeliac, splenic, renal and gastroduodenal arteries in whom endovascular coil embolisation was successfully used to treat a bleeding gastroduodenal artery pseudoaneurysm.

CT Features of Vasculitides Based on the 2012 International Chapel Hill Consensus Conference Revised Classification

Vasculitis, characterized by inflammation of vessel walls, is comprised of heterogeneous clinicopathological entities, and thus poses a diagnostic challenge. The most widely used approach for classifying vasculitides is based on the International Chapel Hill Consensus Conference (CHCC) nomenclature system. Based on the recently revised CHCC 2012, we propose computed tomography (CT) features of vasculitides and a differential diagnosis based on location and morphological characteristics. Finally, vasculitis mimics should be differentiated, because erroneous application of immunosuppressive drugs on vasculitis mimics may be ineffective, even deteriorating. This article presents the utility of CT in the diagnosis and differential diagnosis of vasculitides.

Segmental arterial mediolysis with 5 splenic artery aneurysms. A rare finding of a rare disease: Case report and literature review

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The article represents SAM in SAA which is a rare finding in a rare disease and due to the paucity of sample of cases there is no standardization in the management.

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SAM should be suspected when multiple aneurysms are found in the same anatomic site.

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Angiography is important to detect adjacent involvement. CT angiography of brain should be done to rule out distal vascular disease.

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Endovascular option is the first choice but sometimes it is not feasible, in this case was excluded due to anatomical and configuration reasons.

Introduction

Splenic artery aneurysms (SAA) are uncommon findings. They are usually single and isolated; however they can be multiple; hence vasculopathy and segmental artery mediolysis may be considered.

Presentation of case

In our manuscript we present a case of a 54 year old multiparous lady who was discovered incidentally to have a diseased splenic artery containing five SSAs. The largest aneurysm was close to the takeoff of the vessel and the smallest was distal embedded in the splenic hilum. Endovascular option was technically not feasible. Therefore the patient underwent a complete splenic artery resection with splenectomy and the histopathologic examination was suggestive of segmental arterial mediolysis (SAM).

Discussion and conclusion

Multiple SAAs remains a rare finding of a rare disease. Complications can be crucial and high index of suspicion is important. Segmental arterial mediolysis can be considered in patients with several aneurysms on one anatomic site; Angiography is the gold standard diagnostic and therapeutic method. Complete splenic artery resection with splenectomy is the best treatment option for solitary vessel involvement.

Imaging and clinical findings in segmental arterial mediolysis (SAM)

Segmental arterial mediolysis (SAM) is an uncommon, non-atherosclerotic, non-inflammatory arteriopathy that tends to affect the medium-sized splanchnic branches of the aorta along with renal, carotid, cerebral, and coronary arteries. The clinical presentation ranges from asymptomatic to severe, life-threatening intra-abdominal hemorrhage and shock. SAM overlaps clinically and radiologically with other inflammatory vasculitides. This article describes the pathologic-radiologic correlation, imaging findings, and the management of the disease. Radiologists should be familiar with this disease entity as imaging plays a crucial role in the diagnosis.

Successful microscopic renal autotransplantation for left renal aneurysm associated with segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is an uncommon, nonarteriosclerotic vascular disease. SAM is characterized by lysis of arterial media and can lead to aneurysm formation. The renal arteries are the third most common arteries associated with SAM. We report the case of a 32-year-old man with left renal artery aneurysm associated with SAM. We successfully performed left renal autotransplantation using microscopic vascular reconstruction. SAM is characterized by vascular fragility; therefore, microscopic surgery is favorable for treating aneurysms associated with SAM.

Fatal hemoperitoneum due to segmental arterial mediolysis

Spontaneous hemoperitoneum due to vascular injury is a life-threatening condition mostly associated with aortic or splanchnic arterial disease, which stems from atherosclerotic, inflammatory, or infectious origin. However, in 1976, Slavin and Gonzales described a nonatherosclerotic arterial disease that may render aneurysmal formation predominantly in the splanchnic arterial bed. The clinical presentation is diverse, but abdominal pain and shock prevail. We report the case of a middle-aged man who presented a hemoperitoneum due to a middle colic artery aneurysm rupture and died after undergoing a surgical treatment attempt. The preoperative imaging study revealed the presence of a huge hematoma in the epiplon retrocavity, and abdominal free liquid as well as extensive arterial disease with multiple aneurysms. The autopsy findings included hemoperitoneum, hematoma in the upper left abdominal quadrant, the surgical ligature of the middle colic artery, and histologic features consistent with segmental arterial mediolysis. The authors call attention to this rare entity and highlight the autopsy as a fundamental examination to accurately reach this diagnosis.

Longitudinal Evaluation of Segmental Arterial Mediolysis in Splanchnic Arteries: Case Series and Systematic Review

BACKGROUND

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic, non-inflammatory vascular disorder varying widely in clinical course. The purpose of this study is to analyze detailing clinical and imaging manifestations over time in patients with SAM through a literature review and to suggest an optimal management strategy.

METHODS

A retrospective review of eight consecutive patients diagnosed with SAM between January, 2000 and January, 2012 was conducted. All presented with acute-onset abdominal or flank pain. Clinical features, imaging studies, and laboratory findings served as grounds for diagnosis, having excluded more common conditions (ie, fibromuscular dysplasia, collagen vascular disorders, or arteritis). CT angiography was done initially and repeated periodically (Week 1, Month 3, then yearly). Treatment was conservative, utilizing endovascular intervention as warranted by CT diagnostics. In a related systematic review, all English literature from 1976 to 2015 was screened via the PubMed database, assessing patient demographics, affected arteries, clinical presentations, and treatment methods.

FINDINGS

Ultimately, 25 arterial lesions identified in eight patients (median age, 62.8 years; range, 40-84 years) were monitored for a median period of 26 months (range, 15-57 months). At baseline, celiac axis (3/8, 37.5%), superior mesenteric (4/8, 50%), and common hepatic (2/8, 25%) arteries were involved, in addition to isolated lesions of right renal, splenic, right colic, middle colic, gastroduodenal, left gastric, right gastroepiploic, proper hepatic, right hepatic, and left hepatic arteries. Compared with prior publications, celiac axis and superior mesenteric artery were more commonly affected in cohort. Arterial dissections (n = 8), aneurysms (n = 5), stenoses or occlusions (n = 4), and a single pseudoaneurysm were documented. Despite careful conservative management, new splanchnic arterial lesions (n = 4) arose during follow-up. Considering the few available reports of new arterial lesions in the literature, newly developing pathology is a distinctive feature of our patients, four of whom eventually required endovascular interventions.

CONCLUSIONS

Careful clinical observation via periodic CT angiography is required in patients with SAM, checking for newly developing lesions. The natural history of SAM should be clarified in a larger patient population.

Segmental arterial mediolysis of left gastric artery: a case report and review of pathology

BACKGROUND

Segmental arterial mediolysis (SAM) is a rare non inflammatory vascular disease that can present with massive haemorrhage, which may lead to death without prompt surgical intervention.

CASE PRESENTATION

A 60 years old Aboriginal female presented with life threatening, spontaneous intra-abdominal bleeding requiring an emergency laparotomy. The source of bleeding was found to be ruptured left gastric artery. A total gastrectomy was performed as a damage control procedure. A staged Roux-en-Y oesophago-jejunostomy with Hunt Lawrence pouch reconstruction was undertaken thirty six hours later. Histopathological findings revealed evidence of non-inflammatory segmental vascular damage with microaneurysm, consistent with segmental arterial mediolysis.

CONCLUSION

Prompt resuscitation and surgical intervention can decrease the morbidity and mortality in this rare clinical entity.

Segmental arterial mediolysis: a systematic review of 85 cases

BACKGROUND

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy of unknown etiology with life-threatening manifestations. With advances in endovascular techniques, SAM is increasingly being managed without the need for major surgery.

METHODS

A systematic review of the literature published on SAM between 1976 and 2012 was performed, focusing on arterial involvement, diagnostic imaging modalities, mortality and morbidity rates, and in particular treatment outcomes with open versus endovascular intervention.

RESULTS

Sixty-two studies reporting on 85 cases of SAM were reviewed. Sixty-nine percent of cases were diagnosed histologically (24% on autopsy). Angiography was the most common form of diagnostic imaging modality (56% of cases). Arterial involvement was largely abdominal or cranial, with splenic arterial involvement being the most prevalent (29% of cases). There was a total SAM-related mortality of 26%. Endovascular intervention, most commonly in the form of coil embolization of aneurysmal vessel(s), was successful in 88% of cases where attempted, with no reported mortality. There was a mortality rate of 9% where open surgery was attempted.

CONCLUSIONS

Catheter-based endovascular techniques can be a successful, minimally invasive treatment option in the management of this potentially life-threatening condition, and may also provide a temporary bailout measure in the acute phase before definitive surgical treatment at a later stage.

Rapid progression of a splenic aneurysm due to segmental arterial mediolysis: a rare cause of acute pancreatitis

BACKGROUND

The etiology of acute pancreatitis can be manifold, beside the usual causes. We are reporting an unusual cause that triggered acute pancreatitis.

PATIENT & RESULTS

A 50 year-old male experienced attacks of acute pancreatitis (abdominal pain and elevated amylase and lipase) during sexual arousal. Serial imaging showed a rapidly-progressing, partly-thrombosed splenic artery aneurysm, with local compression of the pancreas. After angiographic coiling, the attacks subsided. Further angiography revealed additional aneurysms consistent with segmental arterial mediolysis at other sites of the body. Molecular analysis regarding Ehlers-Danlos-syndrome and genetic factors for pancreatitis, autoantibodies and Syphilis serology was negative.

CONCLUSIONS

Acute pancreatitis was triggered by a transient rise in blood pressure during sexual stimulation, which caused rapid progression of a splenic artery aneurysm as part of systemic segmental arterial mediolysis.